《Java语言程序设计与数据结构》编程练习答案（第十二章）

英文名：Introduction to Java Programming and Data Structures, Comprehensive Version, 11th Edition

12.1

public class book {
       public static void main(String[] args)    {
           if(args.length!=3){
               System.out.println("fuck you~~");            System.exit(1);        }        int result = 0;        try{
               int opt1 = Integer.parseInt(args[0]);        }        catch (NumberFormatException ex)        {
               System.out.print("Wrong input: "+args[0]);        }        try{
               int opt2 = Integer.parseInt(args[2]);        }        catch (NumberFormatException ex)        {
               System.out.print("Wrong input: "+args[2]);        }    }}

12.2

import java.util.*;public class book {
       public static void main(String[] args)    {
           Scanner input = new Scanner(System.in);        System.out.print("Enter two integers: ");        boolean in1 = true;        boolean in2 = true;        int jojo = 0;        int dio = 0;        while(in1){
               try{
                   jojo=input.nextInt();                in1 = false;            }            catch (InputMismatchException jj){
                   input.nextLine();                System.out.print("Please enter an integer； ");            }        }        while(in2){
               try{
                   dio=input.nextInt();                in2 = false;            }            catch (InputMismatchException jj){
                   input.nextLine();                System.out.print("Please enter an integer； ");            }        }        int sum=jojo+dio;        System.out.print("The sum is "+sum);    }}

12.3

import java.util.*;public class book {
       public static void main(String[] args)    {
           Scanner input = new Scanner(System.in);        int[] ass = new int[100];        for(int i=0;i<100;i++)            ass[i]=(int)(Math.random()*100);        System.out.print("Enter your index: ");        int index = input.nextInt();        try{
               int jj = ass[index];        }        catch (ArrayIndexOutOfBoundsException k){
               System.out.println("Out of Bounds!");            System.exit(1);        }        System.out.println("The number of the index is "+ass[index]);    }}

12.4

👨

12.5

public class book {
       public static void main(String[] args)    {
           try{
               Triangle ass = new Triangle(1,1,4);        }catch(IllegalTriangleException jj){
               System.out.println("You smart ass!");            System.out.println(jj);            System.exit(1);        }    }}class IllegalTriangleException extends Exception{
       private double s1;    private double s2;    private double s3;    public IllegalTriangleException(double aa, double bb, double cc){
           super("Invalid sides "+aa+" "+bb+" "+cc);        s1=aa;        s2=bb;        s3=cc;    }}class Triangle{
       private double s1;    private double s2;    private double s3;    public Triangle(double aa,double bb,double cc)    throws IllegalTriangleException {
           if(aa

12.6

import java.util.*;public class book {
       public static void main(String[] args)    {
           Scanner input = new Scanner(System.in);        System.out.print("Enter a hex-string: ");        String jojo = input.next();        try{
               int dio = hexToDecimal(jojo);            System.out.print(dio);        }catch (NumberFormatException starplatium){
               System.out.print(starplatium);            System.exit(1);        }    }    public static int hexToDecimal (String hex)    throws NumberFormatException{
           int decimalValue = 0;        hex=hex.toUpperCase();        for(int i=0;i
   
    ='A'&&hexChar<='F')||(hexChar>='0'&&hexChar<='9')){
                   decimalValue=decimalValue*16+hexCharToDecimal(hexChar);            }            else{
                   throw new NumberFormatException("Not a hexstring!");            }        }        return decimalValue;    }    public static int hexCharToDecimal(char ch){
           if(ch>='A'&&ch<='F')            return 10+ch-'A';        else            return ch-'0';    }}

12.9

import java.util.*;public class book {
       public static void main(String[] args)    {
           Scanner input = new Scanner(System.in);        System.out.print("Enter a bin-string: ");        String jojo = input.next();        try{
               int dio = binToDecimal(jojo);            System.out.print(dio);        }catch (NumberFormatException starplatium){
               System.out.print(starplatium);            System.exit(1);        }    }    public static int binToDecimal (String hex)    throws BinaryFormatException{
           int decimalValue = 0;        for(int i=0;i

12.10

import java.util.*;public class book {
       public static void main(String[] args)    {
           ArrayList
   
     h = new ArrayList
    
     ();        double i = 114514;        while(true){
               i++;            try{
                   h.add(i);            }            catch(OutOfMemoryError killerQueen){
                   System.out.print("Ohhhhhh!");                System.exit(1);            }        }    }}

12.11

import java.util.*;import java.io.*;public class book {
       public static void main(String[] args)            throws Exception    {
           if(args.length!=2){
               System.out.println("Usage: damn fool!");            System.exit(1);        }        File src = new File(args[1]);        StringBuilder tmp= new StringBuilder();        if(!src.exists()){
               System.out.println("src does not exist!");            System.exit(2);        }        try(Scanner input = new Scanner(src);)        {
               while(input.hasNext()){
                   String jj = input.nextLine();                tmp.append(jj.replaceAll(args[0], "")+'\n');            }        }        src.delete();        File dst = new File(args[1]);        try(PrintWriter output = new PrintWriter(dst);) {
               output.print(tmp);        }    }}